The degenerative cervical spine

Pathophysiology of cervical myelopathy (Review)

Cervical myelopathy is a well-described medulla spinalis syndrome characterized by sensory disorders, such as pain, numbness, or paresthesia in the limbs, and motor disorders, such as muscle weakness, gait difficulties, spasticity, or hyperreflexia. If left untreated, cervical myelopathy can significantly affect the quality of life of patients, while in severe cases, it can cause disability or even quadriplegia. Cervical myelopathy is the final stage of spinal cord insult and can result from transgene dysplasias of the spinal cord, and acute or chronic injuries. Spondylosis is a common, multifactor cause of cervical myelopathy and affects various elements of the spine. The development of spondylotic changes in the spine is gradual during the patient's life and the symptoms are presented at a late stage, when significant damage has already been inflicted on the spinal cord. Spondylosis is widely considered a condition affecting the middle aged and elderly. Given the fact that the population is gradually becoming older, in the near future, clinicians may have to face an increased number of patients with spondylotic myelopathy.

Optimisation of exposure parameters using a phantom for thoracic spine radiographs in antero-posterior and lateral views

INTRODUCTION

To investigate the exposure parameters for thoracic spine/(TS) radiography that allows the image acquisition at the lowest dose possible, while maintaining an adequate image quality/(IQ) to identify all relevant anatomical criteria.

METHODS

An experimental phantom study was conducted, and 48 different radiographs of TS (24 AP/24 lateral) were acquired. The Automatic Exposure Control/(AEC) with the central sensor was used to select the beam intensity, while Source-to-Detector-Distance/(SDD) (AP:115/125 cm; Lateral:115/150 cm), tube potential (AP:70/81/90 kVp; Lateral: 81/90/102 kVp), use of grid/no grid and focal spot (fine/broad) were manipulated. IQ was assessed by observers with ViewDEX. Effective Dose (ED) was estimated using PCXMC2.0 software. Descriptive statistics paired with intraclass correlation coefficient (ICC) were applied to analyse data.

RESULTS

The ED increased with a greater SDD for lateral-view, presenting a significant difference (p = 0.038), however IQ was not affected. For both AP and lateral, the use of grid had a significant effect on ED (p < 0.001). Despite the images acquired without grid had lower IQ scores, the observers considered the IQ adequate for clinical use. A 20% reduction in ED (0.042mSv-0.033 mSv) was observed when increasing the beam energy from 70 to 90 kVp for AP grid in. The observers ICC ranged from moderate to good (0.5-0.75) in lateral and good to excellent (0.75-0.9) for AP views.

CONCLUSIONS

The optimised parameters in this context were 115 cm SDD, 90 kVp with grid for the best IQ and lowest ED. Further studies in clinical setting are necessary to enlarge the context and cover different body habitus and equipment.

IMPLICATIONS FOR PRACTICE

The SDD impacts on dose for TS; Higher kVp and grid are necessary to better image quality.

[Treatment of odontoid fracture combined with lower cervical spinal cord injuries without fracture or dislocation]

Objective

To discuss the clinical characteristics, mechanism, and treatment of odontoid fracture combined with lower cervical spinal cord injuries without fracture or dislocation.

Methods

According to the inclusion and exclusion criteria, 7 male patients aged 37-71 years (mean, 51.4 years), suffered from odontoid fractures combined with lower cervical spinal cord injuries without fracture or dislocation were analyzed retrospectively between June 2007 and October 2015. The trauma causes were traffic accidents in 2 cases, fall in 2 cases, and hit injury in 3 cases. The time from injury to admission was 2 hours to 3 days with an average of 9 hours. According to Anderson-Grauer classification of odontoid fracture, 1 case of type IIA, 3 cases of type IIB, 2 cases of type IIC, and 1 case of shallow type III were found. The cervical spinal cord injuries affected segments included C 4, 5 in 1 case, C 4-6 in 2 cases, and C 5-7 in 4 cases. All the cervical spine had different degenerative changes: 2 of mild, 3 of moderate, and 2 of severe. The lower cervical spinal cord injury was assessed by Sub-axial Injury Classification (SLIC) with scoring of 4-6 (mean, 5.1). The visual analogue scale (VAS) score was used to evaluate the occipital neck pain with scoring of 7.8±1.0; the neurological function was assessed by American Spinal Injury Association (ASIA) as grade B in 1 case, grade C in 4 cases, and grade D in 2 cases; and Japanese Orthopedic Association score (JOA) was 9.2±3.9. For the odontoid fractures, 4 cases were fixed with anterior screw while the others were fixed with posterior atlantoaxial fixation and fusion. For the lower cervical spine, 4 cases were carried out with anterior cervical corpectomy and titanium fusion while the others with anterior cervical disecotomy and Cage fusion.

Results

The operation time was 178-252 minutes (mean, 210.2 minutes); the intraoperative blood loss was 60-140 mL (mean, 96.5 mL) and with no blood transfusion. All incisions healed primarily. All the patients were followed up 12-66 months (mean, 18 months). There was no direct surgical related complications during operation, and all bone grafting got a fusion at 6-9 months (mean, 7.7 months) after operation. There was no inter-fixation failure or loosening. At last follow-up, the VAS score declined to 1.7±0.7 and JOA score improved to 15.1±1.7, showing significant differences when compared with preoperative ones ( t=18.064, P=0.000; t=-7.066, P=0.000). The neurological function of ASIA grade were also improved to grade D in 5 cases and grade E in 2 cases, showing significant difference ( Z=-2.530, P=0.011).

Conclusion

Complex forces and degeneration of lower cervical spine were main reasons of odontoid fracture combined with lower cervical spinal cord injuries without fracture or dislocation. The type of odontoid fracture and neurological deficit status of lower cervical spinal cord were important to guide making strategy of one-stage operation with a satisfactory clinic outcome.